1*73c132c1SArd Biesheuvel /* 2*73c132c1SArd Biesheuvel * linux/arch/arm/include/asm/neon.h 3*73c132c1SArd Biesheuvel * 4*73c132c1SArd Biesheuvel * Copyright (C) 2013 Linaro Ltd <ard.biesheuvel@linaro.org> 5*73c132c1SArd Biesheuvel * 6*73c132c1SArd Biesheuvel * This program is free software; you can redistribute it and/or modify 7*73c132c1SArd Biesheuvel * it under the terms of the GNU General Public License version 2 as 8*73c132c1SArd Biesheuvel * published by the Free Software Foundation. 9*73c132c1SArd Biesheuvel */ 10*73c132c1SArd Biesheuvel 11*73c132c1SArd Biesheuvel #include <asm/hwcap.h> 12*73c132c1SArd Biesheuvel 13*73c132c1SArd Biesheuvel #define cpu_has_neon() (!!(elf_hwcap & HWCAP_NEON)) 14*73c132c1SArd Biesheuvel 15*73c132c1SArd Biesheuvel #ifdef __ARM_NEON__ 16*73c132c1SArd Biesheuvel 17*73c132c1SArd Biesheuvel /* 18*73c132c1SArd Biesheuvel * If you are affected by the BUILD_BUG below, it probably means that you are 19*73c132c1SArd Biesheuvel * using NEON code /and/ calling the kernel_neon_begin() function from the same 20*73c132c1SArd Biesheuvel * compilation unit. To prevent issues that may arise from GCC reordering or 21*73c132c1SArd Biesheuvel * generating(1) NEON instructions outside of these begin/end functions, the 22*73c132c1SArd Biesheuvel * only supported way of using NEON code in the kernel is by isolating it in a 23*73c132c1SArd Biesheuvel * separate compilation unit, and calling it from another unit from inside a 24*73c132c1SArd Biesheuvel * kernel_neon_begin/kernel_neon_end pair. 25*73c132c1SArd Biesheuvel * 26*73c132c1SArd Biesheuvel * (1) Current GCC (4.7) might generate NEON instructions at O3 level if 27*73c132c1SArd Biesheuvel * -mpfu=neon is set. 28*73c132c1SArd Biesheuvel */ 29*73c132c1SArd Biesheuvel 30*73c132c1SArd Biesheuvel #define kernel_neon_begin() \ 31*73c132c1SArd Biesheuvel BUILD_BUG_ON_MSG(1, "kernel_neon_begin() called from NEON code") 32*73c132c1SArd Biesheuvel 33*73c132c1SArd Biesheuvel #else 34*73c132c1SArd Biesheuvel void kernel_neon_begin(void); 35*73c132c1SArd Biesheuvel #endif 36*73c132c1SArd Biesheuvel void kernel_neon_end(void); 37